Catalyst for the metathesis of olefins

Abstract

Improved catalyst for the metathesis of olefins comprising a compound of W with a halogen and with a phenoxy group which can carry substituents. It contains 4 halogen atoms and 2 phenoxy groups per atom of W. Preferably, the phenoxy group is halogenated. This catalyst allows the more rapid carrying out of various types of metathesis reactions, when it is used as a co-catalyst in conjunction with organo-metallic compounds, particularly Al or Sn. Among others, it allows the economical preparation of pheromones. It is practically insensitive to traces of water and oxygen.

We claim: 
     
       1. In the process for the metathesis of olefins by the contact therewith with a catalytic system comprising a compound of tungsten, the improvement which comprises employing as the compound of tungsten, a compound of the formula ##STR20## in which X is halogen, R is an electronegative group or atom, and n is an integer from 1 to 5. 
     
     
       2. The process of claim 1 in which X and R are individually selected from the group consisting of chlorine and bromine and n is at least 2. 
     
     
       3. The process of claim 2 in which there are R moieties in the ortho positions with respect to the oxygen. 
     
     
       4. The process of claim 1 in which the electronegative group is --NO 2 , --SO 3  H, or --CN. 
     
     
       5. The process of claim 1 for the metathesis of olefins without functional groups in which the catalyst system contains at least one organoaluminum compound of the formula R' 3  Al, R'AlX 2 , R' 2  AlX and R' 3  Al 2  X 3  in which R' is a 1 to 6 carbon atom alkyl group and X is chlorine or bromine. 
     
     
       6. The process of claim 1 for the metathesis of olefins containing functional groups in which the catalytic system contains an organotin compound of the formula XaSnR".sub.(4-a) in which R" is a 1 to 6 carbon atom alkyl group, X is halogen and a is 0 to 2. 
     
     
       7. The process of claim 6 in which a is 0. 
     
     
       8. The process of claim 1 in which the catalytic system contains an organic derivative of lead of the formula PbR'" m  X.sub.(4-m) or Pb 2  R'" b  X.sub.(6-b) in which R'" is hydrocarbon group, X is halogen, m is 2 to 4 and b is 2 to 6. 
     
     
       9. The process of claim 8 in which R'" is 1 to 18 carbon atom alkyl group. 
     
     
       10. The process of claim 9 in which R'" is a 1 to 6 carbon atom alkyl group, m is 4 and b is 6. 
     
     
       11. The process according to claim 1 in which said compound of tungsten is di(dichlorophenoxy)tungsten tetrahalide. 
     
     
       12. The process of claim 1 in which said compound of tungsten is di(2,6-dichlorophenoxy)tungsten tetrachloride.